Jefferson township
- County:
- Union County
- County Seat:
- No
- Area (mi²):
- 35.446
- State:
- South Dakota
Jefferson township is located in Union County, South Dakota. Jefferson township has a 2026 population of 95. Jefferson township is currently declining at a rate of -1.04% annually but its population has increased by 4.4% since the most recent census, which recorded a population of 91 in 2020.
The median household income in Jefferson township is $126,250 with a poverty rate of 8.33%. The median age in Jefferson township is 39.6 years: 46.5 years for males, and 37.6 years for females. For every 100 females there are 100.0 males.